From iguana -8 at 8- one.net Mon Oct 14 23:14:49 1996 Received: from one.net for iguana: at :one.net by www.ccl.net (8.8.0/950822.1) id WAA08096; Mon, 14 Oct 1996 22:20:35 -0400 (EDT) Received: from iguana (port-12-26.access.one.net [206.112.194.126]) by one.net (8.7.5/8.7.5) with SMTP id WAA31561 for ; Mon, 14 Oct 1996 22:20:31 -0400 Date: Mon, 14 Oct 1996 22:20:31 -0400 Message-Id: <199610150220.WAA31561;at;one.net> X-Sender: iguana |-at-| mail.one.net X-Mailer: Windows Eudora Version 2.0.3 Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" To: CHEMISTRY ":at:" www.ccl.net From: iguana*- at -*one.net (Ray Crawford) Subject: ab initio bond minimizations Howdy all -- I have a rather unique problem. I have a structure which was resolved from an electron density map. I wanted to compare this structure to another but when I went to do so using ab initio methods, I found that the single point energy of this molecule was horrendously large and any attempts to do energetic geometry minimizations led to different structures (changed torsions and bond angles). Further investigation led me to the conclusion that the main problem is that the errors in bond lengths (as small as they were) were drowning out the effects which I wanted to see the energetic changes for (torsional and angular changes). I recently saw a paper about a topic similar to this (I think it was in the Journal of Computational Chemistry)... If anyone has any references to work in this area or any ideas about how I can go about comparing these structures, I would appreciate it if you passed it on... All information will be promptly summarized and resubmitted... Thanks, Ray Crawford "Absence of proof is not proof of absence..." iguana ^at^ one.net -Richard Levine http://w3.one.net/~iguana The Lost World Micheal Crichton